1. Field of the Invention
The present invention relates to a user apparatus and a base station.
2. Description of the Related Art
In a long term evolution (LTE) system, in order to efficiently support a high traffic area such as a hot spot, a technology called a centralized radio access network (C-RAN) has been investigated with which it is possible to keep apparatus cost low while increasing the number of cells included in the system.
The C-RAN includes one or more remote radio units (RRUs), which are remotely installed base stations, and a baseband unit (BBU), which is a base station as a centralized RRU controller. The RRUs and the BBU are connected to each other by using a common public radio interface (CPRI). The BBU has functions of layer 1 through layer 3 included in an evolved NodeB (eNB) as an LTE base station. An orthogonal frequency division multiplexing (OFDM) signal, generated by the BBU, is sampled and transmitted to the RRU via the CPRI, and transmitted from a radio frequency (RF) functional unit included in the RRU.
FIG. 1 is a drawing illustrating a configuration example of a C-RAN. In an example of FIG. 1, two RRUs are connected to one BBU via CPRIs.